There are times when I think I’d be much happier if I could spend the rest of my life lounging on the sands of the Mediterranean, having someone fan me with palm fronds while feeding me grapes. In other words, life would be better without any stress. Or would it?

According to new research from the University of California, Berkeley, a little stress may not be so bad for us after all. While chronic stress may be harmful, acute (short-term) stress may actually boost our cognitive function. The findings are supported by other research suggesting a little bit o’ stress may have beneficial effects for our brains and bodies. The key, of course, is knowing when we’re too harried for our own good.

What's the Deal?

Before we get into the science, let’s be clear that most of the research in this area involves rats, not humans, so it’s not entirely clear that the findings apply to people. For a while now, researchers have suspected that the effect of stress on the (rat) brain is like an upside-down U: Up to a certain point, stress boosts cognitive function; after that, it starts to take a negative toll[1][2].

In this latest study, researchers wanted to see if short-term stress really would turn regular old rats into geniuses. So they subjected rats to acute stress by confining them in their cages for a few hours. The stress caused the rats’ corticosterone (a stress hormone) levels to shoot up for a few hours, and also caused the growth of new cells in the hippocampus, an area of the brain associated with memory function.

Two days after the stressful event, the researchers tested rats’ memories, and found nothing had changed. But two weeks later, the rats’ memories had significantly improved. Then the researchers got super-techy and figured out that the cells produced after the stressful event were the same cells involved in learning during the second round of memory tests. In other words, the acute stress had made the rats smarter. The scientists concluded that acute stress has a beneficial effect on cognitive function.

Is it Legit?

Possibly. Again, we’re talking about rats here. And while the researchers behind the latest study believe the findings apply to humans as well, there’s currently no way to monitor neural stem cells in the human brain, according to study co-author Daniela Kaufer.

There’s some evidence that acute stress is not only beneficial for rats’ brains, but also for their immune system. Stress hormones released in response to acute stress may warn the immune system about upcoming threats such as an infection [3]. On the other hand, studies of humans suggest that if the immune system is chronically exposed to stress hormones, we may become more susceptible to diseases [4].

Together these findings imply that acute stress—think a job interview or even a ride on a scary rollercoaster—might actually be necessary for our physical and mental health. It’s chronic stress—like being stuck in a bad job or relationship—that causes our health to decline, contributing to issues as serious as heart disease and obesity.

Still, it’s worth noting that some forms of acute stress may actually cause serious damage, as in the case of post-traumatic stress disorder. The UC Berkeley researchers say it’s still unclear why some types of acute stress have positive effects, and others can be so damaging. It might just be a question of individual experience, so it’s worth figuring out where our own optimal stress level lies.

Shana Lebowitz is the senior writer at Greatist, mainly covering new trends in psychology and mental health. When she's not at Greatist HQ, she's reading a novel, baking a batch of cookies, or buying stick-on earrings.